Arborists and Professionals

Features on the Law of Interest to Those Working in the Arborist, Forest Management and Related Fields

We’re ending the week with some cases that discuss expert witnesses and their roles …



Day One – What is an expert witness?

We’re all used to the role of witnesses in trials (at least those of us who have television sets). Sgt. Joe Friday is best known for his machine-gun deadpan “Just the facts, ma’am” (although in fact, he never delivered that line in all the years of “Dragnet”). And that’s what most witnesses — called “lay witnesses” — are required to do: deliver the facts. The thief was wearing a red bandanna, the light was red when the car drove through it, the tree fell and hit Mrs. Brown’s dog “Fifi.” Those are facts.

But there are times when the facts surrounding what happened may not be enough. Evidence may be needed about the extent of the damage, or the condition of a danger tree, or even the adequacy of an inspection program. In such cases, an expert witness is employed.

An expert witness is a witness, who by virtue of education, training, skill, or experience, is found by the court to have knowledge in a particular subject beyond that of the average person, sufficient that a jury may rely upon the witness’s specialized scientific, technical or other opinions about an evidence or fact issue within the scope of their expertise. Such opinions are called “expert opinions.” Expert witnesses may also deliver an expert opinion or testify about facts from the domain of their expertise.

Typically, experts are relied on by both sides to a dispute for opinions on severity of injury, degree of insanity, cause of failure in a machine or other device, loss of earnings, care costs and the like.

Day 2:

(b) Why do we need experts?

Society has gotten much more complex, and there are many times when the fact-finder (we’ll call it the “jury,” although fact-finders can come in many flavors) needs the assistance of an expert who can provide information that the jury needs and cannot get from anywhere else.

A normal, everyday witness can testify that the fast-food joint coffee was hot, but who can testify that the burns that old Mrs. Doe suffered from the coffee could only have come from a liquid that at least 200 degrees? A normal, everyday witness can say the car seemed to be going fast, but who can testify that from the skid marks, the kind of tires, the braking system, and weather and condition of the road surface meant that the car was traveling at 68-72 mph when the brakes were applied? A normal, everyday witness can say that Mr. Hyde fell into the stump-grinding machine, but who can say that it was technically feasible and economical to install a simple clutch switch on the grinder that would have prevented the accident?

In these cases, expert witnesses must be called upon to provide opinion or scientific testimony to enable a jury to reach the ultimate questions of negligence. Expert testimony likewise is critical in a number of different cases arising from trees.

In Katkish v. District of Columbia, 763 A.2d 703 (Ct.App.D.C., 2000), the plaintiff had sued the District for negligence for property damage caused by a tree that fell on his house. The Court held that whether D.C was negligent depended on the standard of care it owed the plaintiff required expert testimony to establish the standard of care to be met by the District. While expert testimony regarding the appropriate standard of care is not necessary for acts “within the realm of common knowledge and everyday experience,” the Court said that “a plaintiff must put on expert testimony to establish the standard of care when the issue in question is ‘so distinctly related to some science, profession or occupation as to be beyond the ken of the average layperson’. The expert’s testimony ‘must clearly relate the standard of care to the practices in fact generally followed by other comparable governmental facilities or to some standard nationally recognized by such units’.” The Court found that an average person is not capable of discerning when a leaning tree may create a dangerous situation requiring an emergency response and whether the likelihood of the tree falling is related to the condition of the tree, the street, or other circumstances.

This is the kind of testimony that must come from an expert witness.

Day Three – How does one become an expert witness?

Dr. Laurence J. Peter, author of “The Peter Principle,” once said that an expert is someone who has made three correct guesses consecutively. In fact, it’s somewhat more complicated. Still, status as an expert witness, like beauty, is in the eye of the beholder. A court must initially find a person qualified as an expert based on his or her

(1) knowledge;
(2) skill;
(3) experience;
(4) training; or
(5) education.

Obviously, education is the first matter that comes to mind. This is perhaps why Gibson’s Law of Expert Testimony holds in a jocular way that “for every Ph.D, there’s an equal and opposite Ph.D.” But a college degree is not the sine qua non of being an expert.

Many times, years of experience, professional certifications and demonstrated competence in the field (such as having been qualified as an expert in the same area by other courts) is sufficient for a court to hold that a witness should be found to be “expert.” Under Federal Rule of Evidence 702 (Rule 702), an expert may be qualified on any of the five bases we have identified. A witness can qualify as an expert even though he or she lacks practical experience, provided that he or she has had received suitable training or education or has otherwise gained the requisite knowledge or skill. The absence of hands-on experience with the subject may be relevant to the court’s determination whether to accept a witness as an expert, but it is not determinative.

For example, in Hyde v. Vermeer Mfg. Co., Slip Copy, 2007 WL 2329688 (W.D.Tex. Aug. 7, 2007), Hiram Hyde had died when he fell into a stump-grinding machine. His family hired a mechanical engineer who was to testify that the machine should have had a safety switch which would have turned the machine off if the operator opened a safety bar. The defendant claimed the expert lacked qualifications. However, the expert had a bachelor’s and a master’s degree in mechanical engineering through the University of Arkansas. His expertise includes industrial equipment, machine design, hydraulics, guarding, and safety engineering. He also has expertise in plant manufacturing, plant engineering, and warnings and instructions, and he had designed machinery using clutch brakes. He was a member of the American Society of Mechanical Engineers, American Society of Metals, and the National Safety Council, and he was involved in the development of safety standards for loading and lift-and-tilt tables through the Material Handling Industry. The expert has used a handlebar stump cutter to cut stumps on his property, including testing his own proposed modification. The Court ruled that while the expert may have limited experience with hydraulically controlled stump cutters, that limited experience would be shared by most mechanical engineers except for those who worked for the defendant. However, the expert’s credentials, training, and experience were sufficient to qualify him as an expert on guarding systems for the stump cutter.

It’s important to note that the credentials of the expert witness are closely linked to the type of opinion being given. In another case, the City of Marlborough, Massachusetts, tried to introduce expert testimony as to the value of private land it had torn up for a water line. The expert was a real estate professional with impressive credentials. However, the court rejected him as an expert, because the value of the land necessarily had to include the value of the timber cut down by the city, and the real estate professional had no expertise in valuing the timber. Smith v. City of Marlborough, 67 Mass.App.Ct. 1104, 852 N.E.2d 137, 2006 WL 2371969 (Mass.App.Ct. 2006).

Ultimately, the answer to how do you get to be an expert may be the same as how do you get to Carnegie Hall: “practice, practice, practice.” But as well, don’t over promise your client. Stick to your expertise.

Day Four – Standards and Rules Governing Expert Witnesses

(a)           Daubert Standard

 In 1993, the Supreme Court heard a case over the effectiveness of a prescription drug, one which had turned into a battle between experts. The decision, Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993), changed the way federal courts did business in the area of expert testimony.  Federal trial judges became the “gatekeepers” of scientific evidence, and must now evaluate proffered expert witnesses to determine whether their testimony is both “relevant” and “reliable,” a two-pronged test of admissibility.

The relevancy of a testimony refers to whether or not the expert’s evidence “fits” the facts of the case. For example, one may invite a meteorologist to tell the jury if it had been raining on the night of the accident. However, the weatherman would not be allowed to testify if the fact that it had rained was not relevant to the issue at hand in the trial.

The reliability prong is just this: In order for expert testimony to be considered reliable, the expert must have derived his or her conclusions from the scientific method.  Whether proffered evidence was based on the scientific method could be deduced from, among other findings:

•             Whether the theory or technique was falsifiable, refutable, and testable.

•            Whether the theory or technique had been subjected to peer review and publication.

•             Whether the theory or technique had a known or potential error rate, and the existence and maintenance of standards concerning its operation.

•             Whether the theory or technique is generally accepted by a relevant scientific community.

Before Daubert, trial courts often preferred to let juries hear evidence proffered by both sides. After Daubert, once certain evidence has been excluded because it failed to meet the relevancy and reliability standard, it will likely be challenged when introduced again in another trial.

According to a 2002 RAND study, the amount of expert testimony by scientists that was excluded from the courtroom rose significantly after Daubert. This rise likely contributed to a doubling in successful motions for summary judgment in which 90% were against plaintiffs.

The five Daubert admissibility factors are:

1.             Has the technique been tested in actual field conditions (and not just in a laboratory)?

2.             Has the technique been subject to peer review and publication?

3.             What is the known or potential rate of error? Is it zero, or low enough to be close to zero?

4.             Do standards exist for the control of the technique’s operation?

5.             Has the technique been generally accepted within the relevant scientific community?

The Supreme Court explicitly cautioned that the Daubert list should not be regarded by judges as “a definitive checklist or test . . .”

Day Five –

(b)    The Federal Rules

The Federal Rules of Evidence governing expert witnesses are the most studied rules, because most of the serious high-stakes litigation occurs in federal courts, and because the federal rules have served as a model for so many states. Since Daubert, the rules have been modified to reflect the standards adopted in that case. The three rules of most relevance are

Federal Rule of Evidence 702: Testimony by Experts

If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.

Federal Rule of Evidence 703: Bases of Opinion Testimony by Experts

The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence in order for the opinion or inference to be admitted. Facts or data that are otherwise inadmissible shall not be disclosed to the jury by the proponent of the opinion or inference unless the court determines that their probative value in assisting the jury to evaluate the expert’s opinion substantially outweighs their prejudicial effect.

Federal Rule of Evidence 705: Disclosure of Facts or Data Underlying Expert Opinion

The expert may testify in terms of opinion or inference and give reasons therefor without first testifying to the underlying facts or data, unless the court requires otherwise. The expert may in any event be required to disclose the underlying facts or data on cross-examination.

Day Six:  Expert Testimony – Some Illustrations

(a) The Standards: Expert testimony, in order to be found reliable by a jury, must (1) be based upon sufficient facts or data, (2) be the product of reliable principles and methods, and (3) have those principles and methods be applied reliably to the facts of the case.   

(b) Application: Example 1: An example of the application of these standards can be seen in Mercer v. South Bend Snowmobiler’s Club, Inc., Case No. 2:030CV-276, 2006 WL 3804884 (N.D.Ind., Dec. 22, 2006).   The plaintiff, Hollie Mercer, sued the South Bend Snowmobiler’s Club for the wrongful death of her husband, Aaron. Mercer and his friends were riding their snowmobiles along a trail operated and maintained by the Club when he collided with a train as he tried to cross railroad tracks that intersected the trail.  The plaintiff submitted an expert report from Stephan Neese, who offered several opinions on topics from the signage used on the trail to lack of notice to the railroad that the trail existed to his belief that Aaron Mercer would not have had adequate time to perceive and stop or avoid the oncoming train.

The trial court held that some of Neese’s opinions should be excluded.  In making determinations of whether an expert’s testimony is reliable, the court considered whether the scientific theory can be and has been tested, whether the theory has been subjected to peer review and publication, the theory’s known or potential rate of error when applied, and whether the theory has been ‘generally accepted’ in the scientific community.  Because not all expert testimony can be neatly examined under these factors, the trial court admitted, the factors are neither definitive nor exhaustive.  Instead, they are flexible to account for the various types of potentially appropriate expert testimony.  Here, the trial court excluded Neese’s opinion that the  Club should have warned the railroad that the crossing was used by snowmobilers, because the opinion was not based on any scientific, technical or specialized knowledge. In fact, according to Neese’s report, it was not based on anything — not a treatise or manual of any kind.  The court said a conclusion without an analysis providing an accepted premise or reliable principles was simply not an appropriate expert opinion.

As for his opinion that Aaron Mercer would not have had adequate time to perceive and stop or avoid the oncoming train, Neese relied on what he said was generally accepted in the literature that the sensory reaction time is 1.5 seconds, based on the numbers provided by the Club’s lighting expert. The problem, the court criticized, was that Neese did not provide any reliable principles or methodology for this conclusion.  Simply, the court said, Neese did not have any idea if he was right. He didn’t refer to a treatise, an encyclopedia, or an article that provided a premise for his opinion that human perception time would be 1.5 seconds in this case. Without such information, the court could not know whether this opinion was reliable.

But Neese did properly apply the facts to a reliable principle and then arrived at a reasonable conclusion on his opinion about proper signage or the tracks. First, he reviewed the facts that the trail required snowmobilers to cross the railroad crossing and that there were no railroad warning signs where the trail met the road. He then analyzed the Indiana Snowmobile Trails Program Manual, which stated that — when installing signs — the trails operator should be familiar with uniform guidelines. Finally, he applied this principle to the facts of the case and opined that the Club had not attempted to determine what uniform warning signs would be adequate for snowmobilers entering the public highway and crossing the railroad tracks.

Day 7:  More Illustrations

(c) Application: Example 2: Another example of an expert opinion that was shot down can be seen in Welch v. Georgia Dept. of Transp., 642 S.E.2d 913 (Ct.App. Ga.,  2007).  Addie D. Welch was killed when her pick-up hit a dump truck at an intersection.  A policeman said the overgrown bushes on the northwest corner of the intersection contributed to the accident.  A sheriff’s department investigator said overgrown shrubs on the vacant property and a “curvature” in the road combined to make the intersection dangerous.

Welch’s expert witness said that Welch’s line of sight was obstructed by overgrown shrubs and trees on the northwest corner of the intersection, the overgrowth extended two feet into the Georgia DOT right-of-way and that DOT was responsible for maintaining the line of sight.  The expert said American Association of State Highway and Transportation Officials’ (AASHTO) guidelines for that intersection require a line of sight of 430 feet. Because of the overgrown vegetation, Welch’s line of sight was between 143 and 277 feet. Claiming that trees and shrubs on the property adjacent to the intersection were negligently maintained and obstructed her line of sight, Welch’s estate sued the Georgia DOT.

Welch had argued that OCGA §50-21-24(8), made DOT liable for failing to inspect its right-of-way.  In order to prevail on this claim, the Court said, Welch had to show that the vegetation extended into DOT’s right-of-way. DOT argues that the overgrowth was on private property.  Although Welch’s expert believed the vegetation encroached on the DOT right-of-way, the Court agreed with DOT’s view that the extent of the right-of-way couldn’t be ascertained without using courthouse records and surveyors.  Because Welch’s expert did not relied on DOT testimony to opine that vegetation extended into the right-of-way, and the Court found that testimony was uncertain as to the location of the right-of-way, Welch’s expert’s opinion that vegetation extended into the right-of-way was disregarded, and plaintiff was found not to have established DOT’s liability.

Day 8:  Another Illustration

(d) Application:  Example 3: In Holts_v_Omaha”>Holts v. City of Omaha, 2002 WL 31002306 (Ct.App. Neb. 2002)  a 13-year old boy was riding a go-cart on the public sidewalk near his home in Omaha when a 60- to 85-year-old green ash tree standing in the right-of-way broke six feet above the ground and fell on him, killing him.

The evidence showed that the City had previously marked the green ash tree — from which large branches previously had fallen — for removal. The tree was hollow inside, and studies showed the tree had lost from 35 to 76% of its strength.  A neighbor had demanded the City remove the tree, but it had not done so.  The City had conducted drive-by examinations, but it could not tell from its records whether the tree had been identified as a danger tree.
The deceased boy’s mother sued the City, and the trial court awarded her $410,000 damages, holding that the City has a duty to remove hazardous trees from its right-of-ways and that the manner in which the City inspected for hazardous trees was “problematic.”  The court found that the tree had been designated for removal years prior to the time it fell, but even if it hadn’t it still should have been removed prior to the time it fell.  Evidence showed that the green ash looked “hollow” where a prior branch tear-out occurred, and expert testimony showed that this alone was sufficient notice that the green ash was a hazard.

The City argued that Nebraska law prohibits experts from giving opinions based on mere “guess or conjecture,” but, the Court said, an expert testifying on decay of the tree over years had properly based his testimony on inspection methods, measurements, and calculations generally accepted among arborists and foresters.  The evidence relied on by the trial court included “external indicators of whether a tree is defective and hazardous are cuts, cavities, branch loss, epicormic sprouts, and bulges.” In addition, the trial court noted the “round hole close to the bottom of the tree … the roots overlapping the curb [and] the branch tear-outs” are all “indicators of a defective tree,” and it accepted the expert’s strength-loss calculations, which were based on a formula which was generally accepted by foresters. The trial court held that the City had reasonable notice that the green ash was hazardous and needed to be inspected and removed, finding the City negligent in failing to remove the green ash.  The City appealed.

The Court of Appeals agreed with the trial court, calling it “a stretch to call [the expert’s] testimony ‘guess’ or ‘conjecture,’ even as it regards ‘dating’ the decay.”  The City argued that under established Nebraska law, Mrs. Holts may not recover without proving that the City had failed to inspect the tree, failed to observe visible signs of substantial decay, and failed to conduct a reasonable investigation prompted by the presence of indications of decay which would have revealed the extent of the decay.  But the Court of Appeals found there was ample evidence in this case of the City’s failure to discover signs that this was a hazard tree that should have been removed.

The City also argued that because a prior decision had favorably reviewed Omaha’s drive-by inspection plan, the trial court erred in “basing its conclusions of negligence on a finding critical of the windshield tree inspection method utilized by the City.”  The City missed an important point, however.  Evidence showed that such inspection is an acceptable method for viewing nonhazardous street trees, but only if inspectors make a more detailed investigation upon finding symptoms of decay.  The expert testimony supported the City’s practice in theory — the drive-bys help inspectors determine whether a specific tree requires closer examination.  But, the Court said, the green ash did not receive closer examination despite several visible indicators of decay.  Other evidence also showed that the green ash had in fact been marked for removal as a hazard tree, but it was not removed. The Court said that either factual scenario supported the verdict.

Monday: Tree law decisions in which expert testimony was employed


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